Single rotor mixer for plastic material



Sept. 3, 1942- c. F. scHNucK 2,295,361 A SINGLE ROTOR MIXER FOR PLASTICMATERIAL Filed Oct. 24, 1959 4 Sheets-Sheet 1 p 8, 1942- c. F. SCHNUCK2,295,361

SINGLE 'ROTOR MIXER FOR PLASTIC MATERIAL Filed 001:. 24, 1939 4Sheets-Sheet 2 gyzvzv o v Sept. 8, 1942. a. F. SCHNUCK SINGLE ROTORMIXER FOR PLASTIC MATERIAL Filed on. 24, 19 59 4 Sheets-Sheet 5 Sept. 8,1942. c. F. scHNucK 7 SINGLE ROTOR MIXER FOR PLASTIC MATERIAL 4Sheets-Sheet 4 Filed Oct. 24, 1959 0 31M v. 1 f

Patented Sept. '8, 1942 UNITED STATES PATENT orrlca SINGLE ltofriilig g-FOR PLASTIC I '1 Carl F. Schnuck, New Haven, Conn, assignor toApplication October 24, 1939, Serial N6. 301,004

6 Claims.

This invention relates to a machine for mixing and kneading plasticmaterial, and more particularly to a machine for mixing rubber, forexample, and compounding it with various inredients.

In processing rubber crude rubber is masticated or kneaded into aplastic mass and usually at the same time is mixed with variousingredients added to the mass of rubber, such as reinforcing pigments,softeners, fillers and vulcanizing agents. It is very essential that themixing operation be complete so that a thorough dispersion of thevarious ingredients through the mass of rubber is'obtained and ahomogeneous product is secured. This is very essential to the uniformityof the product obtained by the mixing operation.

The present invention relates to a device for performing the mixing andkneading operations in a chamber of cylindrical shape, the chamberhaving an internally projecting rib atthe intermediate portion thereofextending generally circumferentially of the chamber over a considerableportion of the circumference. There is provided within the chamber asingle rotorhaving thereon a set of blades at each end, these bladesbeing helically arranged so as to work the material toward the center ofthe chamber from each end thereof past the intermediate rib.

In the past, devices of this general character have been made for thispurpose but in many of such devices it has been found that while themixing action at the center of the chamber adjacent the rib over whichthe material is extruded or forced by the blades, is very thorough andefficient, the same is not true of the action adjacent the chamber ends,so that one part of the mass may be more thoroughly mixed than anotherand as a result it was difllcult to secure a uniform, homogeneousproduct through which the various ingredients were thoroughly dispersed.In the present device this disadvantage has been overcome and a machinehas been produced which not only brings about a thorough and effectivemixing action so as to deliver a completely,

uniform product, but performs the mixing action in a relatively shorttime compared to the time required in the present machines, and also dueto the arrangement and proportions of the device the mixing and kneadingaction may be carried on at a lower temperature than was previously thecase.

These results are obtained in part by arrangin a single cylindricalchamber, as already described, of such proportions that its diameter isat least for commercial use the as great or greater than its length. sothat the greater part of the action takes place adjacent the center ofthe chamber near the zone or the internally projecting rib. The diameterof the chamber being relatively large compared to its length alsoenables more effective cooling to be accomplished, as cooling passagesmay be provided substantially about the entire circumference ofthechamberwhere the mixing action takes place.

One object of the present invention is the provision of a single rotormixer for plastic material of improved and simple construction, whichwill bring about an effective and thorough mixing and mastication of theplastic material introduoed into the chamber of the machine.

A further object of the-invention is the provision of an improved mixingmachine for plastic material having a chamber of cylindrical formationand a bladed rotor operating within the chamber, such that the greaterpart of the mix ing and kneading'action takes place'adjacent the centralpart of the chamber as opposed to the end portions thereof.

provision of a device of the character described provided with acylindrical chamber having an internally projecting extrusion rib on itsinner surface at substantially the central portion of the chamber and abladed rotor operating within the chamber, the blades being'mounted instaggered relation upon each end of the rotor and extending helically toa point beyond thecenter thereof whereby the mass to be mixed will berapidly moved toward the center of the chamber from the ends thereof andforced over the extrusion rib into the other'side of the chamber toproduce a thorough mixing and masticating of the charge of material.

Tothese and other ends the invention consists in the novel features andcombination ofparts to be hereinafter described and claimed.

In the accompanying drawings:

Fig. 1 is a front eievational view of a single rotor mixer embodying myinvention, with the chamber and rotor being shown in section;-

Fig. 2 is a transverse sectional view on line 2-2 of. Fig. 1; a

Fig. 3 is a development view of the rotor as it would appear ifflattened out;

Fig. 4 is an end elevation of the rotor, and

Figs. 5, 6 and 7 are front elevational views of the rotor showing it inprogressive positions during its rotation.

To illustrate a preferred embodiment of my A still further object of theinventionis the the surface of 2 ,aos,se1

invention I have shown a mixer comprising a and to 7. the blades of therotor extend to some base It, having end standards II and I2 risingextent beyond the center line thereof or beyond therefrom, whichstandards are provided with the intermediate extrusion rib 22, but areof less bearings l3 and H to rotatablysupport a rotor height adjacenttheir inner ends as will be hereshaft it upon which is secured a drivinggear ll, 5 inafter explained, so as to leave some clearance driven by apinion II, which may in turn be opposite the rib through which thematerial may actuated from any suitable source of power (not pass overinto the other end of the chamber to shown). be caught, and operatedupon, by the blades in Supported from the standards ii and II are thatend.

end members It and II of annular formation, so Supported by the endmembers It and I! are a that the rotor may pass through the central pairof annular plates 36 and 31 which form the opening therein. Supportedbetween these two end members of the chamber. Just below these plates isthe chamber body 2| of cylindrical formembers are mounted rings 88 and39, held in mation, this body being cored out to provide pas- I place bythe supports 40 and H, which ringsilt sages II for a cooling fluid sothat the temperais closely the openings within the plates It and turemay be regulated during the operation of 31. Secured in the end faces ofthe rotor are the device. It will, of course, be obvious that if annularmembers or rings 42 and 43, which bear it is desired to carry out amixing operation untightly a ainst the rings 38 and 38 so as to closeder a high temperature a heating mediuminstead the chamber ends aboutthe rotor eiiectively and of a cooling medium may be introduced into the'20 prevent anv of the ingredients from beingforcedpassages II. "out ofthe chamber at this point.

Arranged circumferentially of the chamber It will be noted that the endsof the rotor fit body II at substantially the central portion closelyagainst the plates 38 and 31 so as to obthereof is an inwardlyprojecting rib 22, shown viate as far as possible, the entrance of anyof in transverse section in Fig. 1. The chamber is the material betweenthe end of the rotor and provided with an upper charging opening 23 andthese plates. Also, it will be noted from Figs. 8 a lower dischargeopening 24, and from reference and 5 to 7,that the blades 84 arearranged at a to Fig. 2 it will be seen that the inwardly prorelativelylarge angle with respect to the rotor jecting rib 22 extendscircumferentially about the axis so that as these blades attack thematerial inner surface of the chamber from one of these the tendencywill be to drive it toward the central openings to the other. Theseopenings, as shown portion of the chamber instead of around the peinFig. 2, are located at one side of the vertical riphery'thereof, thusmoving the material sharpcenter line of the chamber so that'the ribextends away from the ends of the chamber toward about aconsiderable'portion of the circumferthe intermediate rib and past thisrib int the ence. It will also be noted that the rib is rela- 35. otherend of the chamber.

. tively shallow as compared with the diameter of In Figs. 5, -8 and 7of the drawings, the prothe chamber," and projects inwardly toward thegressive action .of the'rotor and blades thereon is axis of the chambera-relatively shortdistance. shown. For example, in Fig. 5 one of theblades- The chamber may be charged through the hop- I4 lfas arrived atthe point where its outer edge per 25 which leads into the chargingopening 23 A is at the highest point of the circumference of and thisopening may be closed by a plunger 2| the'chainber, audit will be notedthat thetip oi during the operation oi: the machine. Likewise, the bladeat this point works close to the inner the discharge opening 24 is'closed by a door memperiphery of the chamber wall. This is true of herflsecured to a sliding cylinder 28, which cyithe tip of the blade alongitsentire length until inder is slidablymounted on supports 20 and 30the intermediate extrusion rib is reached In carried by the base so thatthe door may be slid- Fig. 6 of the drawings, the rotor has progressedably moved toward the left, as shown in Fig. 1; through a small angle ofits rotation until the to permit the material to be discharged throughcentral portion B of the blade 34 has reached the opening 24 after themixing operation'iscomthe highest point of the chamber, and it will beDleted. noted that the clearance of this-portion oi' the secured to therotor shaft II is a winged or blade is substantially the same as shownbetween bladed rotor II, the body of which may be cored the point Athereof and the chamber wall in Fig.

- out to provide hollow interior passages 32 for the 5; As shown in Fig.7 of the drawings, a further 'shown in Fig. 3, three of these blades 34are ends of the rotor so that during the rotation of eption of atemperature-controlling fluid inrotation of the rotor has taken placeuntil the troduced through the shaft Openings 33. in e e 1 of t g, u hasamved at t Upon each end of the rotor are a number of blades whichproject from the body thereof toward the inner periphery of the chamber.As

substantially opposite the beeat 22, and that there l clearance betweenthe wall as between the fgnd B. It will also be {the blade ll falls awaypoint C, as shown at-D,

provided upon each end of the rotor,-making-six in all, although thisnumber may be variedas desired. The blades at one end of the rotor arearranged in staggered relation with respect ta .those'of the other end,and-it will be notedthgt the blades are arranged helically on thesurfaggg V of the rotor with the leading edge adjacent the V of the blad39 th t-th the latter in the direction of the arrows in Figs. opening Wl, 2 and 4, the charge of material within the into the "rich chamberwill be moved from the end portions toshown in these) iii blade and theextrusion rib he chamber. It will be noted gxtends' beyond the ribclearance between thisn or extruded through the d end of .the chamber,as

ward the center thereof past-the rib 22 and forced The blades of therotor areoi' substantially the over into the other end of the chamberbetween same formation and the action described .with' the wall thereofand the surface of the rotor in respect to one will be repeated eachtime the that end. charge is encountered and picked up by one of n willalso be noted that as shown in Figs. 3 5; the blades. n will be apparentthat,,due to the.

type comprising a casing of substantially cylindrical form providing amixing chamber,-a gradually sloping rib projecting into said chamber atthe middle portion thereof and constricting its diameter, and a rotorhaving a plurality of closely set, sharply pitched, but generallyrounded blades in each end of the chamber to work the material over andpastsaid rib, said blades having their inner ends adjacent the rib butprovided with substantial clearance with respect thereto, said rotorhaving in its face in the region adjacent the rib a tortuousrotorencircling valley or depression skirting the inner ends of saidblades, and said blades making an angle of substantially 60 with therotor axis to work the material in the tortuous path of said valley.

6. A rubber mixing machine of the enclosed type comprising asubstantially cylindrical casing providing a mixing chamber, a graduallysloping rib extending into the chamber midway of its length, and a rotorfor working the material in a tortuous path around the chamber and backand forth over the surface of said rib, said rotor having three bladesin each end of the chamber in staggered relation to the bladesin theopposite end, said blades making an angle of substantially 60 with therotor axis and each having rounded convex front and rear surfaces CARLF. 'scmwcx.

